The present invention relates to management of a multi-tier storage environment, and more specifically, this invention relates to managing data storage based on peak cyclical workloads in a multi-tier storage environment.
A file system defines how files are named and manages how they are placed for storage and retrieval. File system functionality may be divided into two components: a user component and a storage component. The user component is responsible for managing files within directories, file path traversals, and user access to files. The storage component of the file system determines how files are stored physically on the storage device.
In addition, a file system may attempt to efficiently place data in different locations according to the importance of the data and how frequently it is accessed. When a storage system has more than one tier of data storage (e.g., a multi-tier storage system), the placement of the data within these tiers has a dramatic effect on the accessibility of that data. Data placed on a higher tier is more readily and quickly accessible than data placed on a lower tier. This is generally due to the performance capabilities of the data storage devices used in the higher and lower tiers. A multi-tier storage system with automatic data placement management, such as IBM's Easy Tier can automatically place data in its corresponding tier based on its access pattern. The current invention applies to a multi-tier storage system with automatic data placement management.
In an attempt to manage the resources of a multi-tier storage system, sometimes data associated with a workload is moved to a high tier during a cyclical downtime, such as on the weekends, because its demand relative to other data is high due to the long term time view used to determine a workload's demand. However, by moving workloads to the higher tier during downtimes, some individual storage devices may become overloaded or overdriven once the downtime ends, such as at the start of a work week (e.g., Monday). This is because after the downtime, workloads requiring highly demanded data (“hot” data) will once again be recognized as needing to be placed on the higher tier due to their demand relative to other workloads, but since the higher tier has been populated with workloads during the downtime, overall performance of the multi-tier storage system may be negatively affected.